This invention relates to apparatus for use in steelmaking. It relates particularly to apparatus used to obtain a representative sample of molten slag floating on the surface of molten steel contained in a ladle or similar vessel.
Molten steel after it is refined in a steelmaking furnace, such as a basic oxygen furnace, is tapped into a refractory lined ladle where it is refined further at a ladle treatment station and then transferred to a continuous casting machine or poured into ingots. Modern high quality steels are usually further refined and treated at a ladle treatment station to remove impurities such as sulfur by injecting lime, calcium-silicon or magnesium to the steel or adding various other refining or alloying materials. The injection of these refining or alloying materials into the steel is usually done by a submerged lance at the ladle treatment station. The injection of these materials into the steel produces a slag on the surface of the steel.
Analysis of the slag produced on the steel in the ladle is an effective way to monitor the ladle treatment process for the steel. Prior to this invention, steelmakers attempted to obtain samples of the slag for analysis by manually inserting a pipe into the steel in the ladle. Not only is such a practice hot and dangerous, the design of ladle treatment stations frequently prevents access to the ladle for manual slag sampling. Furthermore, the manual sampling often failed to retrieve a representative sample of the slag.